| As the study of joint rock anchor rod mechanical effects,based on 3 d printing technology produced by mining anchor as the prototype of scale on the surface of the anchor rod and precast joint mold,sample preparation and the preparation of different angles of joint anchorage samples,and USES the digital speckle method(DIC)of specimens under uniaxial compression test surface displacement and the strain field change in the process of monitoring,through the observation of pressure sensor(PS)3d printing of joint rock bolt anchorage force,in the final analysis the different strength of rock mass,contrast different anchorage deformation and strength characteristics of rock mass joint Angle and the mechanical effect of anchorage.The paper obtained the following innovative results:(1)In the laboratory,the 3D printing technology was used to print the stainless steel bolt instead of steel wire and steel bar.In this paper,the "STL" file processed by laser scanning bolt and the "STL" file exported by CAD design containing joint die were imported into the 3D printer,and the bolt was printed by stainless steel metal powder.The mechanical properties of the 3D printed bolt were tested to be similar to the mechanical properties of the original mine bolt,and its surface geometry was identical.Considering the international standard of rock mechanics test,this paper adopts the cylindrical specimen is advantageous for the MTS815 easy test,no need to additional processing supporting tooling,joint surface of cylindrical specimen in design and production as far as possible when the mold to ensure the status of present for plane,help in the process of test observation block along a set of joint plane shear effect.(2)H40 high-strength grouting material is used to prepare standard soft rock and medium hard rock jointed rock mass.Granite is selected as the hard rock,and 3D printed bolt is used to anchor the jointed rock mass.In this paper,the angles of jointed rock mass are selected as 15°,30°,45° and 60°.Of anchoring force is obtained by sensors to collect data,digital speckle treatment after get the strain field and displacement field reveals that the joint Angle of shear behavior plays an important role in the control sample,the test results show that the joint is one of the important factors that weaken the strength of rock mass block,when the joint is significantly lower the strength of the block,and with the increase of joint Angle block strength gradually reduced.When the joint Angle is 15°,the overall bearing capacity of the sample is greatly affected by the strength of the block itself,and the main failure of the rock mass is splitting failure.When the joint Angle is 30°,45° and 60°,the overall bearing capacity of the sample is greatly affected by the shear strength of the joint surface,and the reinforcement effect of the bolt on the joint surface is obvious.At this time,the bolt is not only affected by the bonding and shear effect of the rod body,but also with the aid of the binding force provided by the trays assembled on both sides of the bolt to the anchoring sample.The shear failure of the rock mass test block is the main reason for maintaining the bearing capacity of the whole sample.The test method in this paper provides a new way to study the anchoring effect of anchor rod on rock mass.Due to the feasibility of3 D printing,traditional methods such as steel wire,aluminum bar and smooth slide rod will be replaced by 3D printing technology,which will provide a more helpful basis for future laboratory tests.The results of this paper can provide reference for the related research on the reinforcement mechanism of jointed rock bolt. |
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